PHP object-oriented $this-> usage brief description

In a member method, the method of calling a member method is the object name plus the method name, and the format is "object name->method name". But when defining a class, we often don't know what the object name is, so we can't use the object name. At this time, we have to use the pseudo variable $this.

What is $this?

$this means itself. There is a pointer in $this. Whoever calls it points to whoever calls it. It can only be used inside the class.

$this usage example:

Let’s give an example so that everyone can see the meaning of $this more clearly.

<?php
header("content-type:text/html;charset=utf-8");
class Preson{                                                //定义类
  public $name;
  public $age;
  public function __construct($Name,$Age)        //构造函数
  {
     $this -> name = $Name;
     $this -> age = $Age;
     echo &#39;<pre class="brush:php;toolbar:false">&#39;;
     var_dump($this);                  //打印出$this
  }
  public function showInfo(){             //成员方法
     echo "个人信息：";
     echo &#39;<br/>&#39; . "名字是：" . $this -> name . &#39;<br/>&#39; . "年龄是：" . $this -> age;
  }
}
$preson = new Preson("小草",25);           //实例化
var_dump($preson);                    //打印出$this
$preson -> showInfo();
echo &#39;<hr>&#39;;
$preson = new Preson("大树",30);           //实例化
var_dump($preson);                   //打印出$preson
$preson -> showInfo();

From the picture above we can see the comparison of results. The printed results of $this and $preson are the same. That is to say, $preson calls $this and $this points to it, so the results are the same. Therefore, where $this points to is determined by the object being instantiated, and is a pointer to the current object instance. This includes variables and methods. This also confirms what we said above. Whoever calls it will point to it.

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